science:a way of knowing about the natural world Scientific explanations are based on observations and facts that can be confirmed or disproved by other scientists using accepted scientific techniques.

law:a description of how a natural phenomenon will occur under certain circumstancesKepler's Law of Planetary Motion describes the relationship between the time it takes a planet to go around the Sun and the planet's distance from the Sun.

fact:a natural phenomenon repeatedly confirmed by observationIt takes Venus 225 days to go around the Sun.

hypothesis:a possible and testable statement about a natural phenomenonNewton proposed that the force of gravity between two objects depends on the distance between the objects.

theory:a well-substantiated explanation of some aspect of the natural world that typically incorporates many confirmed observations, laws, and successfully verified hypothesesHeliocentricism: the Sun is the center of our solar system.